The present invention relates generally to storage systems and, more particularly, to managing a data center file system involving deployment and storage of virtual machines.
In datacenters, there are thousands of volumes which store virtual machine's images to deploy virtual machine from a storage subsystem to several hosts. Especially if one considers the deployment starting from the storage subsystem, the difficulty is further increased. This is due to the following reasons. First, the host cannot read the volume's files until the end of deploying the volume because the volume is in storage and is not attached onto the host. Second, the virtual machine (VM) may access the volume via a multipath software; the software has its own logical unit number (LUN) on top of the storage provided LUNs which provide the same volume. Therefore, the LUN provided by the storage is hidden by the multipath software's LUN. As a result, it is difficult for the host to find an expected volume.
U.S. Pat. No. 7,143,146 discloses a distributed file system to keeping track of the file's location and state. However, it does not cover the status of the volume. U.S. Pat. No. 7,096,325 discloses methods to attach volume to LUN and detach volume from LUN. However, it does not discuss the status of the volume specified by a file which is on the volume. U.S. Pat. No. 7,555,644 is directed to system and method for operating system image provisioning in a utility computing environment and discloses a technique for provisioning OS image a boot up of a computing server using a pool for OS image copied volume. FIG. 1 of that patent shows a procedure of managing the pool. However, that patent assumes the volume is already attached on the system and does not consider the volume's state.